9-237; Rev 3; 9/ SOT23, Low-Noise, Low-Distortion, Wide-Band, General Description The wideband, low-noise, low-distortion operational amplifiers offer rail-to-rail outputs and single-supply operation down to 2.7V. They draw 2.2mA of quiescent supply current per amplifier while featuring ultra-low distortion (.2% THD+N), as well as low input voltage-noise density (4.nV/ Hz) and low input current-noise density (.fa/ Hz). These features make the devices an ideal choice for applications that require low distortion and/or low noise. For power conservation, the MAX447/MAX4488 offer a low-power shutdown mode that reduces supply current to.µa and places the amplifiers outputs into a highimpedance state. These amplifiers have outputs which swing rail-to-rail and their input common-mode voltage range includes ground. The MAX447 MAX4478 are unity-gain stable with a gain-bandwidth product of MHz. The MAX4488/4489 are internally compensated for gains of +V/V or greater with a gain-bandwidth product of 42MHz. The single MAX447/MAX4476/ MAX4488 are available in space-saving, 6-pin SOT23 and TDFN packages. Applications ADC Buffers DAC Output Amplifiers Low-Noise Microphone/Preamplifiers Digital Scales Strain Gauges/Sensor Amplifiers Medical Instrumentation µmax is a registered trademark of Maxim Integrated Products, Inc. Typical Operating Characteristic VIN EQUIVALENT INPUT NOISE VOLTAGE (nv/ Hz) 2 2 INPUT VOLTAGE-NOISE DENSITY vs. FREQUENCY k k k FREQUENCY (Hz) MAX447 toc2 Features Low Input Voltage-Noise Density: 4.nV/ Hz Low Input Current-Noise Density:.fA/ Hz Low Distortion:.2% THD+N (kω load) Single-Supply Operation from +2.7V to +.V Input Common-Mode Voltage Range Includes Ground Rail-to-Rail Output Swings with a kω Load MHz GBW Product, Unity-Gain Stable (MAX447 MAX4478) 42MHz GBW Product, Stable with A V +V/V (MAX4488/MAX4489) Excellent DC Characteristics V OS = 7µV I BIAS = pa Large-Signal Voltage Gain = 2dB Low-Power Shutdown Mode: Reduces Supply Current to.µa Places Output in High-Impedance State Available in Space-Saving SOT23, TDFN, µmax, and TSSOP Packages PART +Denotes lead-free package. *EP = Exposed paddle (connect to V SS ). Ordering Information TEMP RANGE PIN- PACKAGE Ordering Information continued at end of data sheet. TOP MARK MAX447AUT-T -4 C to +2 C 6 SOT23-6 AAZV MAX447AUA -4 C to +2 C 8 µmax MAX447ASA -4 C to +2 C 8 SO MAX447ATT+T -4 C to +2 C 6 TDFN-EP* +ADD Pin Configurations and Typical Operating Circuit appear at end of data sheet. PART G A IN B W ( M H z) STABLE GAIN (V/V) Selector Guide NO. OF AMPS SHDN MAX447 Yes MAX4476 MAX4477 2 MAX4478 4 MAX4488 42 Yes MAX4489 42 2 Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at -888-629-4642, or visit Maxim s website at www.maxim-ic.com.
ABSOLUTE MAXIMUM RATINGS Power-Supply Voltage (V DD to V SS )...-.3V to +6.V Analog Input Voltage (IN_+, IN_-)...(V SS -.3V) to (V DD +.3V) SHDN Input Voltage...(V SS -.3V) to +6.V Output Short-Circuit Duration to Either Supply...Continuous Continuous Power Dissipation (T A = +7 C) 6-Pin SOT23 (derate 9.mW/ C above +7 C)...727mW 6-Pin TDFN (derate 8.2mW/ C above 7 C)...44mW 8-Pin µmax (derate 4.mW/ C above +7 C)...362mW Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. DC ELECTRICAL CHARACTERISTICS 8-Pin SO (derate.88mw/ C above +7 C)...47mW 4-Pin SO (derate 8.33mW/ C above +7 C)...667mW 4-Pin TSSOP (derate 9.mW/ C above +7 C)...727mW Operating Temperature Range...-4 C to +2 C Junction Temperature...+ C Storage Temperature Range...-6 C to + C Lead Temperature (soldering, s)...+3 C (V DD = +V, V SS = V, V CM = V, V OUT = V DD /2, R L tied to V DD /2, SHDN = V DD, T A = -4 C to +2 C, unless otherwise noted. Typical values are at T A = +2 C.) (Notes, 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Voltage Range V DD (Note 3) 2.7. V Quiescent Supply Current Per Amplifier V DD = 3V 2.2 Normal mode ma I D V DD = V 2. 4.4 Shutdown mode (SHDN = V SS) (Note 2).. µa T A = +2 C ±7 ±3 Input Offset Voltage V OS T A = -4 C to +2 C ±7 Input Offset Voltage Tempco TC VOS ±.3 ±6 µv/ C Input Bias Current I B (Note 4) ± ± pa Input Offset Current I OS (Note 4) ± ± pa Differential Input Resistance R IN GΩ Input Common-Mode Voltage Range Common-Mode Rejection Ratio V CM CMRR Guaranteed by T A = +2 C -.2 V D D -.6 CMRR Test T A = -4 C to +2 C -. V D D -.7 (V SS -.2V) V CM (V DD -.6V) (V SS -.V) V CM (V DD -.7V) T A = +2 C 9 T A = -4 C to +2 C 9 Power-Supply Rejection Ratio PSRR V DD = 2.7 to.v 9 2 db Large-Signal Voltage Gain A VOL R L = kω to V DD /2; V OUT = mv to (V DD - 2mV) R L = kω to V DD /2; V OUT = 2mV to (V DD - 2mV) R L = Ω to V DD /2; V OUT = 3mV to (V DD - mv) 9 2 8 8 µv V db db 2
DC ELECTRICAL CHARACTERISTICS (continued) (V DD = +V, V SS = V, V CM = V, V OUT = V DD /2, R L tied to V DD /2, SHDN = V DD, T A = -4 C to +2 C, unless otherwise noted. Typical values are at T A = +2 C.) (Notes, 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Output Voltage Swing V OUT AC ELECTRICAL CHARACTERISTICS V IN+ - V IN- mv, V DD - V OH 4 R L = kω to V DD /2 V OL - V SS 4 V IN+ - V IN- mv, V DD - V OH 8 2 R L = kω to V DD /2 V OL - V SS V IN+ - V IN- mv, V DD - V OH 3 R L = Ω to V DD /2 V OL - V SS 8 2 Output Short-Circuit Current I SC 48 ma Output Leakage Current I LEAK Shutdown mode (SHDN = V SS ), V OUT = V SS to V DD ±. ±. µa SHDN Logic Low V IL.3 x V D D V SHDN Logic High V IH.7 x V DD V SHDN Input Current SHDN = V SS to V DD. µa Input Capacitance C IN pf (V DD = +V, V SS = V, V CM = V, V OUT = V DD /2, R L tied to V DD /2, SHDN = V DD, T A = +2 C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Gain-Bandwidth Product Slew Rate Full-Power Bandwidth (Note ) GBWP SR MAX447 MAX4478 A V = +V/V MAX4488/MAX4489 A V = +V/V 42 MAX447 MAX4478 A V = +V/V 3 MAX4488/MAX4489 A V = +V/V MAX447 MAX4478 A V = +V/V.4 MAX4488/MAX4489 A V = +V/V.2 Peak-to-Peak Input Noise Voltage e n (P-P) f =.Hz to Hz 26 nv P-P f = Hz 2 Input Voltage-Noise Density e n f = khz 4. f = 3kHz 3. mv MHz V/µs MHz nv/ Hz Input Current-Noise Density i n f = khz. fa/ Hz Total Harmonic Distortion Plus Noise (Note 6) THD + N V OUT = 2V P-P, A V = +V/V (MAX447 MAX4478), R L = kω to GND V OUT = 2V P-P, A V = +V/V (MAX447 MAX4478), R L = kω to GND V OUT = 2V P-P, A V = +V/V (MAX4488/MAX4489), R L = kω to GND f = khz.2 f = 2kHz.7 f = khz.2 f = 2kHz. f = khz.4 f = 2kHz.6 3 %
AC ELECTRICAL CHARACTERISTICS (continued) (V DD = +V, V SS = V, V CM = V, V OUT = V DD /2, R L tied to V DD /2, SHDN = V DD, T A = +2 C.) PERCENTAGE OF UNITS (%) 8 6 4 2 8 6 4 2 PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Total Harmonic Distortion Plus Noise (Note 6) INPUT OFFSET VOLTAGE DISTRIBUTION -2 - -4-3 -2-2 3 4 V OS (µv) THD + N MAX447-8 toc INPUT OFFSET VOLTAGE (µv) V OUT = 2V P-P, A V = +V/V (MAX4488/MAX4489), R L = kω to GND 2 2 - - - -2 OFFSET VOLTAGE vs. TEMPERATURE V COM = V - -2 2 7 2 TEMPERATURE ( C) f = khz. f = 2kHz.8 Capacitive-Load Stability No sustained oscillations 2 pf Gain Margin GM 2 db Phase Margin ΦM MAX447 MAX4478, A V = +V/V 7 MAX4488/MAX4489, A V = +V/V 8 Settling Time To.%, V OUT = 2V step 2 µs Delay Time to Shutdown t SH. µs Enable Delay Time from Shutdown t EN V OUT = 2.V, V OUT settles to.% µs Power-Up Delay Time V DD = to V step, V OUT stable to.% 3 µs Note : All devices are % tested at T A = +2 C. Limits over temperature are guaranteed by design. Note 2: SHDN is available on the MAX447/MAX4488 only. Note 3: Guaranteed by the PSRR test. Note 4: Guaranteed by design. Note : Full-power bandwidth for unity-gain stable devices (MAX447 MAX4478) is measured in a closed-loop gain of +2V/V to accommodate the input voltage range, V OUT = 4V P-P. Note 6: Lowpass-filter bandwidth is 22kHz for f = khz and 8kHz for f = 2kHz. Noise floor of test equipment = nv/ Hz. Typical Operating Characteristics (V DD = +V, V SS = V, V CM = V, V OUT = V DD /2, R L tied to V DD /2, input noise floor of test equipment =nv/ Hz for all distortion measurements, T A = +2 C, unless otherwise noted.) MAX447 toc2 INPUT OFFSET VOLTAGE (µv) 4 3 2 INPUT OFFSET VOLTAGE vs. INPUT COMMON-MODE VOLTAGE V DD = 3V V DD = V % degrees -... 2. 3. 4. INPUT COMMON-MODE VOLTAGE (V) MAX447 toc3 4
Typical Operating Characteristics (continued) (V DD = +V, V SS = V, V CM = V, V OUT = V DD /2, R L tied to V DD /2, input noise floor of test equipment =nv/ Hz for all distortion measurements, T A = +2 C, unless otherwise noted.) OUTPUT VOLTAGE (V) AV (db) AV (db).2.2... 3 2 9 8 7 6 3 2 9 8 7 6 OUTPUT VOLTAGE vs. OUTPUT LOAD CURRENT V DD = 3V OR V V DIFF = ±mv V DD - V OH V OL 2 3 4 6 7 8 9 OUTPUT LOAD CURRENT (ma) LARGE-SIGNAL VOLTAGE GAIN vs. OUTPUT VOLTAGE SWING R L = 2kΩ R L = 2kΩ R L = 2kΩ V DD = 3V R L REFERENCED TO GND 2 2 V OUT SWING FROM EITHER SUPPLY (mv) LARGE-SIGNAL VOLTAGE GAIN vs. OUTPUT VOLTAGE SWING R L = 2kΩ R L = 2kΩ R L = 2kΩ 2 2 V OUT SWING FROM EITHER SUPPLY (mv) MAX447 toc4 MAX447 toc7 MAX447 toc VDD - VOH (mv) AV (db) AVOL (db) 7 6 4 3 2 3 2 9 8 7 7 V DD = V R L REFERENCED TO V DD 6 OUTPUT VOLTAGE SWING (V OH ) vs. TEMPERATURE R L = kω R L = kω - -2 2 7 2 TEMPERATURE ( C) LARGE-SIGNAL VOLTAGE GAIN vs. OUTPUT VOLTAGE SWING R L = 2kΩ R L = 2kΩ R L = 2kΩ MAX447 toc MAX447 toc8 VOL (mv) 7 6 4 3 2 3 2 9 8 7 OUTPUT VOLTAGE SWING (V OL ) vs. TEMPERATURE R L = kω R L = kω - -2 2 7 2 TEMPERATURE ( C) LARGE-SIGNAL VOLTAGE GAIN vs. OUTPUT VOLTAGE SWING V 6 DD = 3V V 6 DD = V R L REFERENCED TO V DD R L REFERENCED TO GND 2 2 2 2 V OUT SWING FROM EITHER SUPPLY (mv) V OUT SWING FROM EITHER SUPPLY (mv) 4 3 2 9 8 LARGE-SIGNAL VOLTAGE GAIN vs. TEMPERATURE R L = kω V OUT = mv TO 4.7V - -2 2 7 2 TEMPERATURE ( C) R L = kω MAX447 toc AV (db) SUPPLY CURRENT (ma) 3. 2. 2.... R L = 2kΩ R L = 2kΩ R L = 2kΩ SUPPLY CURRENT vs. TEMPERATURE PER AMPLIFIER - -2 2 7 2 TEMPERATURE ( C) MAX447 toc6 MAX447 toc9 MAX447 toc2
Typical Operating Characteristics (continued) (V DD = +V, V SS = V, V CM = V, V OUT = V DD /2, R L tied to V DD /2, input noise floor of test equipment =nv/ Hz for all distortion measurements, T A = +2 C, unless otherwise noted.) SUPPLY CURRENT (ma) 3. 2. 2.... SUPPLY CURRENT vs. SUPPLY VOLTAGE PER AMPLIFIER 2. 3. 3. 4. 4... GAIN (db) PSRR (db) SUPPLY VOLTAGE (V) MAX447 toc3 SUPPLY CURRENT (ma) MAX447 MAX4478 GAIN AND PHASE vs. FREQUENCY 6 MAX447 toc6 V DD = 3V OR V 8 R L = kω 44 GAIN 4 C L = 2pF 8 A V = +V/V 3 72 2 36-36 - -72-2 PHASE -8-3 -44-4 -8 k k k M M M INPUT FREQUENCY (Hz) MAX447 MAX4478 POWER-SUPPLY REJECTION RATIO vs. FREQUENCY - V DD = 3V OR V -2-3 -4 - -6-7 -8-9 - - -2-3.., FREQUENCY (khz) 3. 2. 2.... MAX447 toc8 SUPPLY CURRENT vs. OUTPUT VOLTAGE V DD = 3V V DD = V 2 3 4 PHASE (degrees) OUTPUT VOLTAGE (V) GAIN (db) OUTPUT IMPEDANCE (Ω) MAX447 toc4 INPUT OFFSET VOLTAGE (µv) 2 - - - -2 INPUT OFFSET VOLTAGE vs. SUPPLY VOLTAGE 2. 3. 3. 4. 4... SUPPLY VOLTAGE (V) MAX4488/MAX4489 GAIN AND PHASE vs. FREQUENCY MAX447 toc7 6 8 GAIN 44 4 8 3 72 2 36-36 - V DD = 3V OR V -72-2 R L = kω PHASE -8-3 C L = 2pF A V = +V/V -44-4 -8 k k k M M M INPUT FREQUENCY (Hz).. OUTPUT IMPEDANCE vs. FREQUENCY A V = + k k FREQUENCY (Hz) A V = + MAX447 toc9 PHASE (degrees) MAX447 toc 6
Typical Operating Characteristics (continued) (V DD = +V, V SS = V, V CM = V, V OUT = V DD /2, R L tied to V DD /2, input noise floor of test equipment =nv/ Hz for all distortion measurements, T A = +2 C, unless otherwise noted.) THD + N (%) VIN EQUIVALENT INPUT NOISE VOLTAGE (nv/ Hz) 2 2. INPUT VOLTAGE-NOISE DENSITY vs. FREQUENCY k k k FREQUENCY (Hz) MAX4488/MAX4489 TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT VOLTAGE SWING A V = + R L = kω... V DD = 3V, f O = 3kHz FILTER BW = 3kHz V DD = +3V, f O = 2kHz FILTER BW = 8kHz. 2 3 OUTPUT VOLTAGE (V P-P ) MAX4488/MAX4489 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY. FILTER BW = 8kHz R L = kω TO GND R = 2.43kΩ, R 2 = kω V OUT = 2.7V P-P MAX447 toc2 MAX447 toc23 MAX447 toc26 THD + N (%) 2nV/div...Hz TO Hz P-P NOISE V DD = 3V OR V V P-P NOISE = 26nV P-P s/div MAX447 toc2 MAX4488/MAX4489 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY A V = +, V DD = 3V FILTER BW = 22kHz A V = +, V DD = V R L = kω TO GND R =.6kΩ, R2 = 3kΩ V OUT = 2V P-P. k k k 2k FREQUENCY (Hz) MAX447 MAX4478 LARGE-SIGNAL PULSE RESPONSE MAX447 toc27 MAX447 toc24 2.V THD + N (%) THD + N (%) MAX447 TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT VOLTAGE SWING A V = + R L = kω... f O = 2kHz, FILTER BW = 8kHz f O = 3kHz, FILTER BW = 3kHz. 2 3 4 OUTPUT VOLTAGE (V P-P ) MAX447 MAX4478 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY. FILTER BW = 8kHz V OUT = 2V P-P A V = + R L = kω R L TO V DD /2 R L TO GND. R L TO V DD k k k 2k FREQUENCY (Hz) MAX447 MAX4478 SMALL-SIGNAL PULSE RESPONSE MAX447 toc28 MAX447 toc22 MAX447 toc2.6v THD + N (%). 2mV/div. A V = +, V DD = 3V.V.V. A V = +, V DD = V k k k 2k µs/div 4µs/div FREQUENCY (Hz) V DD = 3V, R L = kω, C L = pf V DD = 3V, R L = kω, C L = pf V IN = 2V V IN = mv PULSE 7
Typical Operating Characteristics (continued) (V DD = +V, V SS = V, V CM = V, V OUT = V DD /2, R L tied to V DD /2, input noise floor of test equipment =nv/ Hz for all distortion measurements, T A = +2 C, unless otherwise noted.) MAX4488/MAX4489 LARGE-SIGNAL PULSE RESPONSE µs/div V DD = 3V, R L = kω, C L = pf V IN = 2mV PULSE, A V = +V/V MAX447/ MAX4488 MAX447/ MAX4488 MAX447 toc29 V OUT 2mV/div PIN MAX4476 MAX4488/MAX4489 SMALL-SIGNAL PULSE RESPONSE µs/div V DD = 3V, R L = kω, C L = pf V IN = 2mV PULSE, A V = +V/V MAX4477/ MAX4489 MAX447 toc3 MAX4478 SOT23/TDFN SO/µMAX SOT23/TDFN SO/µMAX SO/TSSOP 6, 7, 7, 8, 4.6V V OUT mv/div.v CROSSTALK (db) -2-3 -4 - -6-7 -8-9 NAME OUT, OUTA, OUTB, OUTC, OUTD MAX4477/MAX4478/MAX4489 CROSSTALK vs. FREQUENCY k k M M M FREQUENCY (Hz) Pin Description FUNCTION Amplifier Output 2 4 2 4 V SS to ground for singlesupply Negative Supply. Connect operation 3 3 3 3, 3,,, 2 4 2 4 2, 6 2, 6, 9, 3 IN+, INA+, INB+, INC+, IND+ IN-, INA-, INB-, INC-, IND- Noninverting Amplifier Input Inverting Amplifier Input 6 7 6 8 4 V DD Positive Supply MAX447 toc3 8 SHDN, N.C. Shutdown Input. Connect to V DD for normal operation (amplifier(s) enabled). No Connection. Not internally connected. EP (TDFN only) EP (TDFN only) EP Exposed Paddle. Connect to V SS. 8
Detailed Description The singlesupply operational amplifiers feature ultra-low noise and distortion. Their low distortion and low noise make them ideal for use as preamplifiers in wide dynamicrange applications, such as 6-bit analog-to-digital converters (see Typical Operating Circuit). Their highinput impedance and low noise are also useful for signal conditioning of high-impedance sources, such as piezoelectric transducers. These devices have true rail-to-rail ouput operation, drive loads as low as kω while maintining DC accuracy, and can drive capactive loads up to 2pF without oscillation. The input common-mode voltage range extends from (V DD -.6V) to 2mV below the negative rail. The push-pull output stage maintains excellent DC characteristics, while delivering up to ±ma of current. The MAX447 MAX4478 are unity-gain stable, while the MAX4488/MAX4489 have a higher slew rate and are stable for gains V/V. The MAX447/MAX4488 feature a low-power shutdown mode, which reduces the supply current to.µa and disables the outputs. Low Distortion Many factors can affect the noise and distortion that the device contributes to the input signal. The following guidelines offer valuable information on the impact of design choices on Total Harmonic Distortion (THD). Choosing proper feedback and gain resistor values for a particular application can be a very important factor in reducing THD. In general, the smaller the closedloop gain, the smaller the THD generated, especially when driving heavy resistive loads. The THD of the part normally increases at approximately 2dB per decade, as a function of frequency. Operating the device near or above the full-power bandwidth significantly degrades distortion. Referencing the load to either supply also improves the part s distortion performance, because only one of the MOSFETs of the push-pull output stage drives the output. Referencing the load to midsupply increases the part s distortion for a given load and feedback setting. (See the Total Harmonic Distortion vs. Frequency graph in the Typical Operating Characteristics.) For gains V/V, the decompensated devices MAX4488/MAX4489 deliver the best distortion performance, since they have a higher slew rate and provide a higher amount of loop gain for a given closed-loop gain setting. Capacitive loads below pf do not significantly affect distortion results. Distortion performance is relatively constant over supply voltages. R G V IN Figure. Adding Feed-Forward Compensation mv V A V = +2 R F = R G = kω R F 2µs/div Figure 2a. Pulse Response with No Feed-Forward Compensation A V = +2 R F = R G = kω 2µs/div Figure 2b. Pulse Response with pf Feed-Forward Compensation C Z V IN mv/div V OUT mv/div V IN mv/div V OUT mv/div V OUT 9
Low Noise The amplifier s input-referred noise-voltage density is dominated by flicker noise at lower frequencies, and by thermal noise at higher frequencies. Because the thermal noise contribution is affected by the parallel combination of the feedback resistive network (R F R G, Figure ), these resistors should be reduced in cases where the system bandwidth is large and thermal noise is dominant. This noise contribution factor decreases, however, with increasing gain settings. For example, the input noise-voltage density of the circuit with R F = kω, R G = kω (A V = +V/V) is en = 4nV/ Hz, en can be reduced to 6nV/ Hz by choosing R F = kω, R G =.kω (A V = +V/V), at the expense of greater current consumption and potentially higher distortion. For a gain of V/V with R F = kω, R G =.kω, the en is still a low 6nV/ Hz. Using a Feed-Forward Compensation Capacitor, C Z The amplifier s input capacitance is pf. If the resistance seen by the inverting input is large (feedback network), this can introduce a pole within the amplifier s bandwidth resulting in reduced phase margin. Compensate the reduced phase margin by introducing a feed-forward capacitor (C Z ) between the inverting input and the output (Figure ). This effectively cancels the pole from the inverting input of the amplifier. Choose the value of C Z as follows: C Z = x (R F / R G ) [pf] In the unity-gain stable MAX447 MAX4478, the use of a proper C Z is most important for A V = +2V/V, and A V = -V/V. In the decompensated MAX4488/ MAX4489, C Z is most important for A V = +V/V. Figures 2a and 2b show transient response both with and without C Z. Using a slightly smaller C Z than suggested by the formula above achieves a higher bandwidth at the expense of reduced phase and gain margin. As a general guideline, consider using C Z for cases where R G R F is greater than 2kΩ (MAX447 MAX4478) or greater than kω (MAX4488/MAX4489). Applications Information The combine good driving capability with ground-sensing input and rail-to-rail output operation. With their low distortion and low noise, they are ideal for use in ADC buffers, medical instrumentation systems and other noise-sensitive applications. V A V = + V DD = +V R L = kω 4µs/div V IN 2V/div V OUT 2V/div Figure 3. Overdriven Input Showing No Phase Reversal V V 2µs/div Figure 4. Rail-to-Rail Output Operation V OUT V/div Ground-Sensing and Rail-to-Rail Outputs The common-mode input range of these devices extends below ground, and offers excellent commonmode rejection. These devices are guaranteed not to undergo phase reversal when the input is overdriven (Figure 3). Figure 4 showcases the true rail-to-rail output operation of the amplifier, configured with A V = V/V. The output swings to within 8mV of the supplies with a kω load, making the devices ideal in low-supply voltage applications. Power Supplies and Layout The operate from a single +2.7V to +.V power supply or from dual supplies of ±.3V to ±2.7V. For single-supply operation, bypass the power supply with a.µf ceramic
SERIAL INTERFACE 3.9kΩ % CS SCLK DIN 7.87kΩ % 22pF 47pF.kΩ % +V +2.V +V capacitor placed close to the V DD pin. If operating from dual supplies, bypass each supply to ground. Good layout improves performance by decreasing the amount of stray capacitance and noise at the op amp s inputs and output. To decrease stray capacitance, minimize PC board trace lengths and resistor leads, and place external components close to the op amp s pins. Typical Application Circuit The Typical Application Circuit shows the single MAX447 configured as an output buffer for the MAX4 6-bit DAC. Because the MAX4 has an unbuffered voltage output, the input bias current of the op amp used must be less than 6nA to maintain 6-bit accuracy. The MAX447 has an input bias current of only pa (max), virtually eliminating this as a source V DD U MAX4ESA DGND 3 2 V 4 REF OUT AGND 8 /2 MAX4477.µF.kΩ % 3.83kΩ % 3 2 7 4 3.7kΩ % 22pF.kΩ % 8 Typical Application Circuit SHDN U2 MAX447AUA 6 6 to +2.V OUTPUT Typical Operating Circuit 22pF /2 MAX4477.kΩ % 7 7.kΩ % 22pF of error. In addition, the MAX447 has excellent openloop gain and common-mode rejection, making this an excellent ouput buffer amplifier. DC-Accurate Lowpass Filter The offer a unique combination of low noise, wide bandwidth, and high gain, making them an excellent choice for active filters up to MHz. The Typical Operating Circuit shows the dual MAX4477 configured as a th order Chebyschev filter with a cutoff frequency of khz. The circuit is implemented in the Sallen-Key topology, making this a DC-accurate filter.
2 3 4 6 7 MAX4478 SO/TSSOP OUT V SS 2 3 4 4 MAX447 MAX4488 SO/µMAX OUTD INA- 3 IND- 2 IND+ OUTA INA- INA+ V DD INB+ INB- OUTB V SS INC+ 9 INC- 8 OUTC 8 7 V DD 6 OUT V SS SHDN OUT N.C. IN+ 6 V DD 2 MAX4476 N.C. OUTA INB- INA+ V SS 6 V DD 2 MAX447 MAX4488 3 4 SOT23-6 SHDN IN- 2 3 4 MAX4477 MAX4489 SO/µMAX *EP = EXPOSED PADDLE. VDD 6 N.C. Pin Configurations 8 7 6 + MAX4476 V DD OUTB N.C. INA- INA+ V SS INB+ IN- IN- 4 VDD 6 OUT SHDN MAX447 MAX4488 *EP VSS 4 2 3 TDFN IN+ IN+ 3 4 IN- *EP SOT23-6 + 2 3 OUT VSS IN+ *EP = EXPOSED PADDLE. TDFN 2
Ordering Information (continued) PART TEMP RANGE PIN- PACKAGE TOP MARK MAX4476AUT-T -4 C to +2 C 6 SOT23-6 AAZX MAX4476ATT+T -4 C to +2 C 6 TDFN-EP* +ADF MAX4477AUA -4 C to +2 C 8 µmax MAX4477AUA -4 C to +2 C 8 µmax MAX4477ASA -4 C to +2 C 8 SO MAX4478AUD -4 C to +2 C 4 TSSOP MAX4478ASD -4 C to +2 C 4 SO MAX4488AUT-T -4 C to +2 C 6 SOT23-6 AAZW MAX4488AUA -4 C to +2 C 8 µmax MAX4488ASA -4 C to +2 C 8 SO MAX4488ATT+T -4 C to +2 C 6 TDFN-EP* +ADE MAX4489AUA -4 C to +2 C 8 µmax MAX4489ASA -4 C to +2 C 8 SO +Denotes lead-free package. *EP = Exposed paddle (connect to V SS ). Chip Information MAX447/MAX4476 TRANSISTOR COUNT: 9 MAX4477 TRANSISTOR COUNT: 232 MAX4478 TRANSISTOR COUNT: 4244 MAX4488 TRANSISTOR COUNT: 9 MAX4489 TRANSISTOR COUNT: 232 PROCESS: BiCMOS 3
Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.).6±..6±. 8 Ø.±. D E H 4X S BOTTOM VIEW 8 DIM A A PACKAGE OUTLINE, SOT 6L BODY INCHES MIN MAX -.43.2.6.37..4..7.6.2.26 BSC A2.3 b c D e E.6 H.88 L.6 α S.27 BSC.2.98.26 6 2-8 G MILLIMETERS MIN MAX -....7.9.2.36.3.8 2.9 3..6 BSC 2.9 3. 4.78.3.4.66 6.2 BSC 6LSOT.EPS 8LUMAXD.EPS A2 A A e b c L α FRONT VIEW SIDE VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, 8L umax/usop APPROVAL DOCUMENT CONTROL NO. REV. 2-36 J 4
Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.).6±. e Ø.±..6±. 4X S H BOTTOM VIEW S α PACKAGE OUTLINE, TSSOP 4.4mm BODY INCHES 2-66 G DIM A A MIN -.2 MAX.43.6 MIN -. MAX.. A2.3.37.7.9 D.2 3..8 D2 E E2 H L L b e c.6.4.6.4.87.7.2.8.99.27 MILLIMETERS 2.9 2.89 2.9 2.89 4.7.4 3. 3. 3...7.37 REF.94 REF.7.6.77.27.97 BSC. BSC.3.78.9.2.96 REF.498 REF 6 6 TSSOP4.4mm.EPS LUMAX.EPS D2 E2 GAGE PLANE A2 A c D b A α E L L FRONT VIEW SIDE VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, L umax/usop APPROVAL DOCUMENT CONTROL NO. 2-6 REV.
Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) N D e B A FRONT VIEW E A H C L SIDE VIEW -8 INCHES MILLIMETERS DIM MIN MAX MIN MAX A.3.69.3.7 A.4...2 B.4.9.3.49 C.7..9.2 e. BSC.27 BSC E..7 3.8 4. H.228.244.8 6.2 L.6..4.27 VARIATIONS: DIM D D D INCHES MIN MAX MIN MAX N MS2.89.97 4.8. 8 AA.337.344 8. 8.7 4 AB.386.394 9.8. 6 AC PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE,." SOIC APPROVAL MILLIMETERS DOCUMENT CONTROL NO. REV. 2-4 B SOICN.EPS 6
Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) PIN INDEX AREA D COMMON DIMENSIONS SYMBOL MIN. MAX. A.7.8 D 2.9 3. E 2.9 3. A.. L.2.4 k.2 MIN. A2.2 REF. E A DETAIL A PACKAGE VARIATIONS PKG. CODE N D2 E2 e JEDEC SPEC b [(N/2)-] x e T633-6.±. 2.3±..9 BSC MO229 / WEEA.4±..9 REF T633-2 6.±. 2.3±..9 BSC MO229 / WEEA.4±..9 REF T833-8.±. 2.3±..6 BSC A A2 MO229 / WEEC E2 b L N.3±. LC e.9 REF D2.3x.3 -DRAWING NOT TO SCALEk PACKAGE OUTLINE, 6,8, & 4L, TDFN, EXPOSED PAD, 3x3x.8 mm DOWNBONDS ALLOWED NO NO NO e 2-37 L C PIN ID e [(N/2)-] x e REF. L G 2 6, 8, &L, DFN THIN.EPS T833-2 8.±. 2.3±..6 BSC MO229 / WEEC.3±..9 REF T833-3 8.±. 2.3±..6 BSC MO229 / WEEC.3±..9 REF NO YES T33-.±. 2.3±.. BSC MO229 / WEED-3.2±. 2. REF NO T433-4.7±. 2.3±..4 BSC - - - -.2±. 2.4 REF YES T433-2 4.7±. 2.3±..4 BSC - - - -.2±. 2.4 REF NO PACKAGE OUTLINE, 6,8, & 4L, TDFN, EXPOSED PAD, 3x3x.8 mm -DRAWING NOT TO SCALE- 2-37 G 2 2 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 2 San Gabriel Drive, Sunnyvale, CA 9486 48-737-76 7 2 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.